


Listen to the Beat

by amazingpages



Category: Teen Wolf (TV)
Genre: Accidental Voyeurism, Alternate Universe - Human, Derek and Stiles are Neighbors, Fluff and Crack, M/M, Masturbation, Plot What Plot/Porn Without Plot, Secret Crush, idk how to tag this it's really just ridiculous, there really isn't any plot
Language: English
Status: Completed
Published: 2015-01-19
Updated: 2015-01-19
Packaged: 2018-03-08 07:06:07
Rating: Mature
Warnings: Creator Chose Not To Use Archive Warnings, No Archive Warnings Apply
Chapters: 1
Words: 5,561
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/3200051
Author URL: https://archiveofourown.org/users/amazingpages/pseuds/amazingpages
Summary: <blockquote class="userstuff">
              <p>Of all the things Derek thought he'd have to deal with upon moving into his new apartment, a loudly masturbating neighbor wasn't one of them.</p>
            </blockquote>





	Listen to the Beat

**Author's Note:**

  * For [Cassidy_Doris](https://archiveofourown.org/users/Cassidy_Doris/gifts), [catlechat](https://archiveofourown.org/users/catlechat/gifts).



> This fic was written because my upstairs neighbor masturbates in a very loud fashion, and if that’s not fodder for fic then I don’t know what is.

Derek sits down in his desk chair and plops the heavy cardboard box down in front of him. He just moved into his new apartment last week so he’s still getting settled in, but this box is his last one to unpack and then he will officially be _moved in_.

It feels good to have a place of his own. He and Cora shared an apartment for years, up until a few months ago; New York rent isn’t cheap, and he didn’t really have a reason to live by himself. Now that Cora’s living with her long-term boyfriend, however, Derek’s on his own. He stayed the last few months in their old apartment until the lease was up and then moved about twenty minutes east, to a more affordable part of the city. Granted, the apartment’s no penthouse, but it’s not terrible. His bedroom isn’t separated from the living area by a curtain, so he counts it as a win.

He doesn’t really mind living on his own. It was time for a change of pace, and it’s not like he can’t afford it now that he’s got a steady job. The first few days, it was a little weird not seeing Cora every day, but he’s quickly becoming accustomed to the privacy that comes with living by himself. He can walk around naked any time he wants—that alone is reason enough to enjoy his new apartment.

Derek isn’t naked now though, having just gotten home from work. It was a long day at the office, but before he does anything else he wants to get this box sorted and out of the way so he can just be done with it. Tie loosened around his neck and sleeves rolled up, Derek begins shuffling through the various junk in the box. He hadn’t been very methodical about packing his stuff, which meant most of his belongings were tossed into whichever box was closest. It made for efficient packing, but unpacking it all is a bitch. Nothing is sorted properly and he doesn’t know where anything is until it’s all taken out. 

This box seems to have mostly junk in it: knick knacks, mail he never bothered to go through, a few unmatched socks. Derek pulls out a grungy towel and is about to toss it towards his hamper when he hears a muffled creak. The unexpected sound makes him jump (though he’ll never admit it) and he looks around for the source of it. Despite staying frozen for a few moments to listen for it, the noise doesn’t repeat, so Derek continues on with his sorting. 

He doesn’t pause again until a thumping sound distracts him, and this time Derek can tell it’s coming from the apartment upstairs. It sounds kind of like someone is hammering something, and Derek wonders if the tenant above him has just moved in as well. It was only a few days ago that Derek himself was putting together a new TV stand with far too many pieces, slightly worried that the sound of hammer and nails would disturb his neighbors. 

The neighbor upstairs seems to have no issue with bothering anyone else though, because the hammering continues on rather steadily, an odd creak mixed into the mash of noises. Derek can’t help but roll his eyes. There hasn’t been much chance to meet any of his neighbors, not between work and moving and everything else, but until now he hasn’t had any issues with them. When he lived with Cora, they had a neighbor whose newborn kept everyone on their floor awake half the night, so really a bit of hammering during the day is mild in comparison. 

It isn’t until Derek hears a moan interspersed in the thumping that he realizes there’s no furniture being built upstairs. His eyes widen as the moans erupt more frequently, the creaking sound paired with the thumping now giving Derek a mental image of a very rickety bed. He doesn’t know what to do with himself and he sits frozen in place, listening to the sounds for far longer than he means to.

Dropping the old baseball trophy he’s holding, Derek turns around in his desk chair to open his laptop. The messenger tab is still open from the day before and he sighs with relief when he sees his friends are online. Good. They’ll know what to do.

 **Derek:** my upstairs neighbor is jerking off!

 **Derek:** loudly!!

 **Isaac:** how can you tell?

 **Derek:** the repeated thumps and moans are good hint :P

 **Erica:** come onnnnn, we need _details_!

 **Boyd:** why are you even listening?

 **Derek:** i didn’t eavesdrop on purpose! i’m in _my own_ apartment

 **Cora:** go upstairs and ask if you can join the party

Derek doesn’t know why he thought they’d be _helpful_. He’s stuck here, listening to his faceless neighbor rub one out for the entire complex to hear, while his friends (which includes his younger sister, unfortunately) make the situation even more awkward. The pace of the thumping increases suddenly and Derek grows more frantic for a solution. He can’t just sit here and _listen_.

 **Derek:** what do i do???

 **Erica:** i need more info to work with than this

 **Cora:** yeah, why are you being so stingy?

 **Erica:** ohh, snapchat us a video of it!

 **Derek:** what? no!

 **Cora:** don’t be a spoilsport!!

 **Erica:** it’s not fair that you get to have all the fun

 **Boyd:** they’re not gonna stop whining until you do it

Derek knows Boyd is right, so after a bit more protest he finally agrees and gets out his phone, pulling up the Snapchat app that Cora downloaded to it before she moved out. She had told him it was a fun way to keep in touch, but somehow he never imagined using it for these circumstances. Holding down the button on the screen, he records the sounds for a few seconds before letting go and watching the video.

 **Derek:** you can’t even hear it on the video

 **Cora:** get closer, loser!

 **Erica:** yeah, come on! we wanna hear!

Derek rolls his eyes, lamenting in his choice of friends as he stands up and climbs onto his bed. Holding his phone up near the vent in his ceiling and feeling like both a creeper _and_ a moron, Derek records a video again, this time with more success. He sends it to Cora, Erica, and Isaac. Boyd doesn’t have a smartphone, but Derek knows he’ll watch it on Erica’s.

 **Isaac:** he sounds pretty hot

 **Erica:** i’d do him

 **Cora:** i still think you’re missing out on some prime sexytimes

 **Derek:** i’d prefer it if my sister stopped discussing my sex life

 **Cora:** your sister has a _name_

 **Erica:** she’s right though, you should totally hit that

 **Derek:** i don’t even know who he is. i’ve never seen him

 **Cora:** there’s an easy solution to that

 **Derek:** CORA

 **Cora:** okay _fine_ i’ll stop

 **Cora:** for now

A much more intense moan sounds from upstairs and then there’s blessed silence. Derek heaves a quiet sigh of relief. He’s not sure what he would have done if it had gone on for much longer. It’s not that he’s against masturbating. Derek watches porn just like anyone else, and yeah, sometimes the sounds alone are enough to get him off. But somehow listening to something so personal this close to home is different. He’s not sure how to feel about it.

 **Derek:** he’s done

 **Cora:** finally

 **Erica:** seriously. what was that, like 15 minutes?

 **Isaac:** dude needs to learn how to beat off properly

 **Erica:** idk, i like a guy with stamina

 **Boyd:** you _have_ a guy with stamina

 **Erica:** oh yes i do, baby

 **Derek:** are you two seriously flirting online while in the same room?

***

Derek has almost forgotten about the entire embarrassing ordeal a few days later when a tell-tale thump interrupts his dinner. Well, it’s not really dinner so much as cereal in a cup, but he couldn’t be bothered to actually cook anything. As it is, he still spills milk down the front of his shirt and then glares at the ceiling. For a moment, he hopes that the thump was an anomaly, but almost as if reading his mind the thumping starts up again in full force.

He only hesitates a moment before setting his cereal aside and reaching for his laptop.

 **Derek:** HELP HE’S DOING IT AGAIN

 **Erica:** okay srsly get a grip

 **Isaac:** who’s doing what?

 **Boyd:** his neighbor is jerking off

 **Isaac:** oh right. so what’s the problem exactly?

 **Cora:** derek’s too chickenshit to go upstairs

 **Derek:** OH COME ON

 **Cora:** what? it’s true

 **Isaac:** should have listened to her last time, dude

 **Derek:** i’m not going up there!

 **Erica:** why not?

Derek can’t even believe they’re having this discussion. There are so many reasons not to go up there. One of the primary ones being he needs to be able to look his neighbors in the eye without knowing which one it is. Ignoring his friends’ ongoing conversation, Derek pulls over the pad of paper that is sitting on his desk and grabs a pen.

He’ll just write his neighbor a polite note to keep it down next time.

Unlike the crude things his friends are currently suggesting, he’ll settle this like an adult. Maybe the prior tenant down here was someone older, with poor hearing. The guy upstairs may not even know how loud he’s being. He’ll probably be embarrassed about the noise and be a little quieter after that. _Derek_ would want to know if he was being loud without realizing it, so he’ll just do this guy the courtesy of dropping an anonymous hint. And _not_ the kind of hints Cora is still suggesting.

 **Erica:** derek? are you still there?

 **Erica:** dereeeeeeeeek

 **Cora:** holy shit he went upstairs! i didn’t think he’d do it

 **Isaac:** boyd, you owe me 5 bucks

 **Derek:** i’m still here

 **Derek:** and really, isaac?

 **Cora:** aw man.

 **Erica:** where’d you disappear to?

 **Derek:** i was writing him a note

 **Isaac:** a love note?

 **Derek:** seriously?

 **Isaac:** sorry dude

 **Erica:** sounds like derek’s deflecting

 **Derek:** it’s not a love note!

 **Derek:** it’s a common courtesy note

 **Cora:** what the hell is a common courtesy note?

 **Derek:** it’s politely letting him know that he’s being kind of loud while he’s...you know

 **Erica:** cora your brother’s never getting laid

 **Cora:** i know it’s pathetic

***

Despite what his sister says, Derek is _not_ pathetic. He’s just a good neighbor, is all. Which is why he waits until it’s very late to go deliver the note to avoid any awkward encounters. There’s no way he’s going to risk the chance of running into the guy right outside of his own door, so it’s three A.M. before Derek deems it safe enough to venture upstairs. His upstairs neighbor is most likely asleep by now. Grabbing the note from where he’d left it on his desk, Derek trudges out to the hall in his pajama pants and a pair of socks. He takes the elevator because even though it’s only one floor up, it’s also _three A.M._ and Derek can’t be bothered to take the stairs.

When the elevator chimes, announcing its arrival at the next floor, the doors open and Derek exits, careful to muffle his footsteps. He feels a bit of a thrill at sneaking around in the middle of the night and can’t help but smile a little to himself. See? This was a way better idea than coming up here _while_ the guy is jerking off.

Upon reaching the door, Derek glances down to look over the note one last time.

_Neighbor,_

_I know this might seem a little embarrassing, but I thought I’d let you know that I can hear you when you’re masturbating. Don’t worry, I’m not mad or anything! I’m sure you don’t mean to be so loud. Just, you might try toning it down a little? Thanks._

_Derek_

Satisfied, Derek crouches down and shoves the slip of paper under the guy’s door. Now he can wipe his hands of this entire thing and enjoy his _quiet_ evenings in peace. Humming softly to himself, he takes the elevator back down a level, locks up his apartment, and heads into his room.

It isn’t until Derek is climbing into bed that he realizes he _signed the freaking note_.

***

His neighbor is being loud on purpose.

Derek is sure of it. Yeah, okay, it was a pretty dumbass move to sign the _anonymous_ note that he left for his neighbor, but he really can’t be blamed for doing something out of habit. Besides, the note was totally polite. He does not deserve this kind of punishment. Sure, it’s an unusual and kind of sexy punishment, but _that is not the point_.

The point is that his neighbor is clearly being louder tonight to get back at Derek. Not to mention, Erica’s comment about stamina was spot-on, because the guy’s been going at it for a good twenty minutes now, with no signs of stopping. The thumping is definitely louder, the moans filthier, and the bed just won’t. Stop. Creaking.

It may be driving Derek a little insane.

And, okay, maybe part of the reason he’s feeling so uncomfortable is because between being annoyed by all the moaning and thumping and creaking going on upstairs, Derek’s actually getting a little turned on. But then he only has to think about the fact that he could potentially be getting sexually excited over someone’s grandpa; that’s pretty much a boner killer.

He doesn’t bother to message his friends this time. Mostly, he doesn’t want to read the “I told you so” responses they’re all sure to send him. The note was clearly a disaster. He doesn’t need them to rub it in. Despite all of that, after another ten minutes pass with no letup, Derek yanks a pad of paper towards himself angrily and scrawls out yet another note to deliver:

_At least buy a new mattress._

***

The next day, Derek sleeps in. It’s Saturday and he’s had a long week, so he feels like he deserves it. He spends the day lying around his apartment, eating stale chips and watching TV, only venturing out to make a trip down to the lobby to check his mailbox. It’s when he is pulling the envelopes out of his box that he happens to glance at the box above his own. **Apt. 47** , the one that belongs to his upstairs neighbor. Before he can stop it, his eyes slide down to the little tag right below it that reads _Stilinski_.

Derek would like to say that he has moral objections to stalking someone, but when it comes to the internet, anything goes. Paired with his awkwardness in person and his inability to hold casual conversations, most of what he knows about other people tends to come from online, barring his few close friends. And now, faced with the knowledge of his neighbor’s name? It’s kind of a miracle that he lasts ten minutes before he caves and looks up Stilinski on Facebook.

It isn’t hard to narrow down who it is, since only three Stilinskis live within one-hundred miles of the city. There’s also no need for him to worry about being aroused by the geriatric community any longer. Stiles Stilinski, according to Facebook, is no old man. In fact, he’s one hell of an attractive guy. A couple years younger than Derek, even, but who’s counting? Stiles is incredibly tempting. His honey brown eyes, plush lips, and legs that go on for days. The pictures Derek clicks through are creating a tantalizing mental image for him.

As if on cue, the rhythmic thumping starts upstairs. Based on the tell-tale squeaking that accompanies it, Stiles blatantly ignored the note Derek slipped under his door the previous night. But Derek’s mind really isn’t focused on how annoying the mattress is, because the picture of Stiles still pulled up on his computer screen is practically mocking him for his salacious thoughts. Having a visual to go along with the moans that are drifting down through the ceiling turns him on even more than he thought possible, and before Derek’s even realized what he’s doing, he’s got a hand palming his erection through his sweatpants.

It’s difficult to ignore his hard-on now, whether he wants to or not (he really, _really_ doesn’t). He finds himself stroking himself in time with his neighbor, listening to the beat of the bed against the wall. His grip tightens with each filthy moan he hears, and Derek begins touching himself with renewed fervor, rubbing his thumb across the head of his cock with each downstroke. The fabric of his pants provides just the right amount of friction, and he can feel pleasure building in the base of his spine after just a few minutes.

He knows, from his somewhat voyeuristic experiences, that his neighbor can go on for quite awhile before reaching completion, but Derek’s not sure if he’ll get that far. His eyes have drifted shut of their own accord, but when he opens them after a particularly loud thump, he sees Stiles smirking back at him from his computer screen and can’t help the low groan that escapes his lips as he tips over the edge. Derek continues stroking himself through the aftershocks, slumping a little lower in his chair and listening shamelessly until Stiles finishes as well.

As much as he’d like to continue sitting there, lazing about in typical post-orgasm fashion, he soon remembers why coming in his pants is really a _terrible_ idea and goes to clean up. It takes little effort to wipe himself down and change into a new pair of pants, but he finds himself thinking about Stiles long after the muffled sounds and shuffling footsteps from upstairs have ceased.

***

Two weeks later, Derek opens his front door only to find Cora standing on the other side holding a bag of chips and a six-pack of beer, looking mildly pissed off. To be fair, Cora tends to function in a general state of annoyance—as she laments quite frequently, “People annoy me.”—but Derek can tell when she’s seriously upset.

“Um, hi?” he says, stepping aside to let her through.

“Ryan’s having a bro day and if I had to listen to one more stupid fart joke I was gonna rip them all a new asshole,” Cora greets, setting her things on the small kitchen counter and then dropping onto his couch.

Derek refrains from mentioning that Cora is usually the one that _makes_ the fart jokes, and instead grabs a bottle opener from his utensil drawer. “Wanna watch a movie?”

“Will you judge me if I choose something that’s total trash?”

“Only a little,” Derek concedes, tossing her the remote. He opens a beer for both of them and then joins her on the couch. She’s flipped the channel to some Lifetime movie where the couple is currently arguing about something. The plot is nonexistent, and he spends the next thirty minutes just trying to figure out which of the three dudes involved is really the kid’s father, since they started the movie when it was already halfway over. Derek’s just starting to get invested in the drama that’s unfolding when he hears a squeak and a thump and can’t help but groan out loud in frustration.

“What?” Cora asks, glancing away from the screen.

“Nothing,” Derek grumbles as the now-familiar thumping sound emanates from his ceiling.

“No way.” Cora’s eyes grow wide. “Is that him? But it’s the middle of the afternoon!”

Derek doesn’t bother to respond. It used to be that he only had to deal with the sounds happening sometime in the evening (usually after Derek got home from work), but apparently his neighbor has an exceedingly high sex drive and no other outlets. Lately, it seems like the guy masturbates any time Derek’s in his apartment. It happens morning, noon, and night, with little exception. Not to mention, ever since Derek wrote those notes, the thumping is loud enough that he can’t even tune it out with some music or, in this case, the TV.

Seeing Derek’s mounting irritation, Cora abruptly stands, shoving her empty bottle at his chest. “I’ll handle this.”

“ _What_?” Derek jumps to his feet, following her to his entryway. “Cora, no!”

Cora ignores his protests, looking resolute as she marches out the door and leaving Derek gaping after her in horror. It isn’t until she’s halfway down the hall that Derek’s mind kicks back into gear and he jogs up the steps behind her, catching her right as she reaches Stiles’ door. Cora has just raised her fist to knock when Derek grabs it, but not before it has a chance to connect. However, the door apparently wasn’t shut all the way, because it inches open from the small push.

“ _Cora_ ,” Derek hisses. “Don’t you dare!”

“So, clearly this guy is incompetent as well as annoying,” Cora comments, pushing open the unlocked door and ignoring Derek’s protests. “Enough is enough,” she says over her shoulder.

Derek stands frozen in the doorway, unsure whether to follow her or just pack up his apartment while he has the chance. There’s no way he’ll live this down, either way. It makes him cringe to think of what Cora might say, but he can neither bring himself to stop her or just walk away. Cursing his own cowardice and indecision, he scans Stiles’ apartment absentmindedly for lack of anything else to do.

It’s a mirror image of his own apartment below, though a far sight messier. There are dirty dishes on the counter, snack wrappers crammed between the couch cushions, and an insane number of video games strewn around the room. The walls are covered with Star Wars posters and painted a tacky shade of red that makes Derek cringe. He watches as Cora sidesteps a nasty looking pair of socks and follows the obnoxious thumping sounds back to the bedroom where the door is also standing slightly ajar. She looks back at Derek once, gives him a wink, and nudges the door open.

For a second, Derek wonders at her bravado as she stands in the doorway and stares at the scene before her. But then Cora barks out an astonished laugh and Derek cringes as Stiles lets out a surprised yelp. Derek hears a crash and thump and can only assume that Stiles fell out of bed. Cora doesn’t try to stifle her laughter, and Derek almost feels sorry for his neighbor. He’s been on the receiving end of Cora’s rude humor enough times to know it isn’t fun. After a few moments, Cora walks far enough into the room that Derek can no longer see her. He hears a bit of shuffling and a grunt or two, but little else.

“So, _you’re_ the chronic masturbator,” Cora finally says, her voice carrying through the apartment.

Derek can’t hear Stiles’ response, but there’s a muttered conversation going on before, “Your _brother_?”

Derek slaps a palm to his forehead as the conversation fades back into quiet tones. He wonders what he could have possibly done in another life to deserve this kind of torture.

“Well, he did leave some notes…”

“Of _course_ he did,” Cora says. Derek can practically hear the eye roll that accompanies her response.

After a few more minutes of hushed conversation, Derek’s ready to just turn tail and hide forever in his apartment when Cora exits the bedroom, a wide smile on her face.

“Ready to go?” she asks, brushing by him as though she _didn’t_ just spend ten minutes talking to his masturbating neighbor.

“Um...Cora?”

***

In the following week, Derek comes to regret ever letting Cora go upstairs in the first place.

He curses the day she was born and every day leading up to this entire fiasco with his upstairs neighbor, because somehow through all of it Stiles and Cora became _friends_. She texts Stiles, sends him stupid cat memes, and Derek even sees a picture of the two of them hanging out on Cora’s facebook page.

Since Derek is annoyed, and awkward, and very inconveniently horny due to Stiles’ loud and frequent masturbation, he is completely unable to even look Cora in the eye anymore.

 _How_ is this his life?

Cora refuses to tell him what happened between her and Stiles that day, but Derek knows it can’t be anything good. He’s still seething about their absurd friendship a few days later when, after over a week of denying himself, Derek can’t take it anymore. He’s bent over his desk, hand braced on the top as he rubs one out, silently berating himself as he listens to the throaty moans coming from Stiles’ apartment.

There’s no way for him to pretend he’s doing anything other than getting off to the sound of Stiles, but that doesn’t mean he has to like it. His mind’s eye has already produced a mental image of Stiles (courtesy of Facebook) to go along with the sound effects, and Derek has to bite his lip against the groan seeking to escape as he slides his hand along his cock, rolling his hips to gain more friction.

“ _Fuck_ ,” he mutters, when Stiles moans again.

It’s to easy to envision Stiles spread out before him, writhing into his mattress. Derek imagines that mouth, its wet warmth wrapped around him. He pictures Stiles kneeling in front of him, those sweet moans muffled by Derek’s thick cock. His body flushes with heat and it only takes a few more strokes before he’s coming all over his desk, forehead pressed against the surface as he tries to catch his breath.

***

The next morning, Derek is woken up an hour earlier than usual by the fire alarm blaring in his apartment. It’s been almost two months since Mrs. Robertson tried to reheat something with the foil wrapper still attached, but Derek is still grumpy because it’s _six in the freaking morning_. He doesn’t bother getting dressed, instead shuffling down the stairs with everyone else in just his boxers and a pair of slippers, grabbing his phone as an afterthought.

He’s in the middle of playing Candy Crush while waiting for the fire department to give the all-clear when he gets a text from Cora.

_> nice slippers, bro._

Derek sighs. It’s too early in the morning for this.

_< are you seriously stalking me right now?_

_> i have friends in high places_

Derek rolls his eyes, looking up at the people around him from his perch on the curb. There’s no way Cora bothered to get out of bed this early, she’s even more of a sloth than he is. He scans the crowd blearily, but his eyes narrow when they land upon a certain, gangly man about twenty feet away. Stiles looks ridiculous in Batman boxers and a large robe that flaps around his knees as he walks from person to person, chatting and laughing with them all like they’re old friends.

_< if that’s a reference to my upstairs neighbor, you’re not funny_

_> he DOES live on the 4th floor_

There’s a photo attached to her text, and when Derek clicks on it he sees it’s a blurry picture of him, perched on the curb outside of his building in nothing but his boxers and slippers. Before he can type out a response, she sends him another picture, this time a screenshot of her facebook newsfeed.

_> i see you’re having fun_

_< go away_

_> you’re practically naked just do him already and get it over with_

_< MY SEX LIFE IS OFF LIMITS CORA_

Derek resolutely puts his phone on silent, ignoring when a text message alert from Cora pops up on his screen. And he absolutely does not keep glancing at Stiles and his unfairly hot bedhead while waiting to go back inside.

He _doesn’t_.

***

Things come to a head a few days later. It’s almost like Stiles is putting on a show on purpose, the way his _me time_ seems to coincide so frequently with Derek’s routine. Derek knows it only got worse after he wrote those damn notes, but he doesn’t know what else to do to make it stop.

So he jerks off. Again.

Only, maybe this time he isn’t as quiet as he’d like to think, because when he’s getting ready to go grocery shopping an hour later he finds a slip of paper that had been shoved haphazardly under his front door. Upon further inspection, it’s actually half of a torn envelope, and a note has been scrawled across the back of it:

_Dear Neighbor,_

_I know this might seem a little embarrassing, but your whole ‘stifled grunts and moans’ routine is getting a little old. If you’re going to masturbate, could you at least spice it up a little? Just a suggestion. Kudos on the strong finish, though! 10/10 would listen again._

_Sincerely,_ _Your Friendly Neighborhood Spiderman_

Derek is seething by the time he finishes reading the letter. There’s no doubt who it’s from, and he can just imagine the smirk on Stiles’ face as he wrote it. As if masturbating to the sound of his upstairs neighbor isn’t bad enough, now Stiles _knows_ about it. The thought is enough to fuel his anger, and there is clearly only one course of action to take. Before he can talk himself out of it, Derek’s stomping up the stairs to the fourth floor and knocking rudely on Stiles’ door.

Stiles opens it a few moments later, that exact smirk already on his face. “Took you long enough, big guy. I see you got my note.”

Derek shoves Stiles into his apartment with a palm to his chest, smiling to himself as Stiles’ smirk changes to a look of confusion.

“Whoa, hold up, dude. It was just a joke,” Stiles says, a hint of uncertainty in his voice. “What are you doing?”

Derek doesn’t stop, however, crowding Stiles backwards until his back is pressed up against his bedroom door.

“Isn’t it obvious?” Derek says in a low voice, his mouth by Stiles’ ear. “I’m spicing things up.”

He doesn’t wait for a response before diving in to kiss those tempting lips, but Stiles clearly gets the message. Derek feels Stiles’ hands grip his shirt as he coaxes Stiles’ mouth open, sliding his tongue into that welcoming heat. The groan it elicits from Stiles is so much better than any muffled sounds he could hear from downstairs, and he presses closer, melding their bodies together and pressing one strong thigh between Stiles’ legs.

“I should’ve written a note weeks ago,” Stiles gasps out between kisses, one of his hands wandering down Derek’s back to grab his ass as Stiles’s hips roll against his.

Derek chuckles, pressing open-mouthed kisses down Stiles’ throat just to elicit more of those sounds. “You’ve been driving me _insane_ ,” he murmurs, sucking on the tender skin below Stiles’ ear. “Do you know how hard it is to focus with you beating off all the time?”

At that, Stiles’ smirk is back, but it dissolves quickly beneath Derek’s bruising kisses. When they break away again to breathe heavily against one another, Stiles replies, “Why don’t you show me?”

“You’d better hope your neighbors aren’t home,” Derek replies, a predatory look in his eye as he ushers Stiles into his bedroom.

***

“Well, it all started because I couldn’t stop talking about Derek,” Stiles says through a mouthful of Doritos. Erica grabs the bag from him and steals a huge handful before allowing Stiles to take it back.

Everyone is in Derek’s apartment as they marathon old horror films, and despite the fact that Derek’s only actually known Stiles for a few days now, he fits right in with his friends. They all get along seamlessly, especially after they got tired of making terrible jokes about Derek finally growing some balls and boning his neighbor.

“I mean, I didn’t know who he was at the time, but my friend Scott got sick of hearing about my hot neighbor,” Stiles continues. “So, he bet me that I couldn’t masturbate often enough to get him to actually do something about it.”

“Yeah, well, apparently you _couldn’t_ masturbate often enough,” Cora interrupts, “since I walked in on you jumping up and down on your bed while trying to play Mario Kart.”

The group erupts into laughter while Stiles splutters indignantly on the couch.

“You promised you wouldn’t tell!” he protests.

Cora just shrugs and smirks, throwing popcorn at Stiles’ head.

“Besides, do you know how hard it is to control Princess Peach without being stationary?”

“Who’s Princess Peach?” Derek asks, but the judgemental looks from his friends tell him this is a question he probably should have kept to himself.

Stiles pats his thigh. “Don’t worry, Derek. Now that I’m not pretending to jerk it off five times a day, we’ve got plenty of time to teach you.”

“I don’t think your bed could have taken much more abuse anyway,” Isaac adds.

Derek smirks. “I dunno. It seems to have adapted to two of us pretty well.”

There are exasperated groans all around, but Derek and Stiles share private grins, and Derek is suddenly very glad that he moved in beneath this obnoxiously perfect man.

**Author's Note:**

> Cas also wrote a fic based on my neighbor's escapades! It's [here](http://archiveofourown.org/works/2356241) if you'd like to read it. :)
> 
> As always, feel free to visit me on [tumblr](http://miss-emrys.tumblr.com/)!
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> 
> As a bonus, here's a conversation I had with my friends, Carrie and Cas, the first time I heard my upstairs neighbor masturbating:
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> * * *


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